Java - Byte parseByte() method

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Description

The Java Byte parseByte(String s) parses the string argument as a signed decimal byte. The characters in the string must all be decimal digits, except that the first character may be an ASCII minus sign '−' ('\u002D') to indicate a negative value or an ASCII plus sign '+' ('\u002B') to indicate a positive value.

The resulting byte value is returned, exactly as if the argument and the radix 10 were given as arguments to the parseByte(java.lang.String, int) method.

Declaration

Following is the declaration for java.lang.Byte.parseByte() method

public static byte parseByte(String s)throws NumberFormatException

Parameters

s − a String containing the byte representation to be parsed

Return Value

This method returns the byte value represented by the argument in decimal.

Exception

NumberFormatException − if the string does not contain a parsable byte.

Example 1

The following example shows the usage of Byte parseByte() method to parse strings with signs. We're creating two byte variables and two string variables with valid values. Then using parseByte() method we're getting bytes and then result is printed.

package com.tutorialspoint;
public class ByteDemo {
   public static void main(String[] args) {

      // create 2 byte primitives bt1, bt2
      byte bt1, bt2;

      // create and assign values to String's s1, s2
      String s1 = "+123";
      String s2 = "-123";

      /**
       *  static method is called using class name. 
       *  assign parseByte result on s1, s2 to bt1, bt2
       */
      bt1 = Byte.parseByte(s1);
      bt2 = Byte.parseByte(s2);

      String str1 = "Parse byte value of " + s1 + " is " + bt1;
      String str2 = "Parse byte value of " + s2 + " is " + bt2;

      // print bt1, bt2 values
      System.out.println( str1 );
      System.out.println( str2 );
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Parse byte value of +123 is 123
Parse byte value of -123 is -123

Example 2

The following example shows the usage of Byte parseByte() method to parse strings without signs. We're creating two byte variables and two string variables with valid values. Then using parseByte() method we're getting bytes and then result is printed.

package com.tutorialspoint;
public class ByteDemo {
   public static void main(String[] args) {

      // create 2 byte primitives bt1, bt2
      byte bt1, bt2;

      // create and assign values to String's s1, s2
      String s1 = "123";
      String s2 = "14";

      /**
       *  static method is called using class name. 
       *  assign parseByte result on s1, s2 to bt1, bt2
       */
      bt1 = Byte.parseByte(s1);
      bt2 = Byte.parseByte(s2);

      String str1 = "Parse byte value of " + s1 + " is " + bt1;
      String str2 = "Parse byte value of " + s2 + " is " + bt2;

      // print bt1, bt2 values
      System.out.println( str1 );
      System.out.println( str2 );
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Parse byte value of 123 is 123
Parse byte value of 14 is 14

Example 3

The following example shows the usage of Byte parseByte() method to parse strings with invalid values. We're creating two byte variables and two string variables with invalid values as values are beyond range. Then using parseByte() method when we attempt to get a byte, the NumberFormatException will be thrown.

package com.tutorialspoint;
public class ByteDemo {
   public static void main(String[] args) {

      // create 2 byte primitives bt1, bt2
      byte bt1, bt2;

      // create and assign values to String's s1, s2
      String s1 = "1234";
      String s2 = "14";

      /**
       *  static method is called using class name. 
       *  assign parseByte result on s1, s2 to bt1, bt2
       */
      bt1 = Byte.parseByte(s1);
      bt2 = Byte.parseByte(s2);

      String str1 = "Parse byte value of " + s1 + " is " + bt1;
      String str2 = "Parse byte value of " + s2 + " is " + bt2;

      // print bt1, bt2 values
      System.out.println( str1 );
      System.out.println( str2 );
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Exception in thread "main" java.lang.NumberFormatException: Value out of range. Value:"1234" Radix:10
	at java.base/java.lang.Byte.parseByte(Byte.java:154)
	at java.base/java.lang.Byte.parseByte(Byte.java:178)
	at com.tutorialspoint.ByteDemo.main(ByteDemo.java:18)